My French is limited, but a bit of Googling reveals that "filante" means "thread-spinning" in French. I'm guessing the word connects somewhere to the Latin root of the English word filament. So étoile filante literally translates to mean a star with thread spinning out the back, which is quite a good description I suppose.
Of course the thing that falls to earth in the Tintin book isn't exactly a regular shooting star - ie: a meteor briefly burning with friction-generated heat as it passes through the Earth's atmosphere. The meteor in this story is observed to be aflame for many hours before it reaches the Earth's atmospere, when it's still out in space, more like a comet. So maybe Hergé was deliberately making it clear that this wasn't supposed to be a normal shooting star, when he picked L'Étoile mystérieuse instead of L'Étoile filante as the book's title.
Do people think the English translators were right to change it, or would a more exact translation - The Mysterious Star - have been a better title? | 
